(A) Technical Field
The present invention relates generally to axial flow devices and more particularly, to a bio-mechanical apparatus comprised substantially of golden ratio geometry and proportions which is capable of functioning as a turbine or a pump in gas or liquid flow currents and more specifically, relates to vertical axis wind turbines.
(b) General Background
Air has mass; when it moves it has force which can be felt, heard and seen, it is the wind. Wind is not a constant force, there are gusts and lulls as well as shifts in direction. Certain archaeologists suggest that wind power was used by the ancients in China and Persia. One of the first Persian windmills was a vertical axis wind turbine (VAWT); and was made of papyrus reeds that were formed into flat sail shapes. This was what is referred to as a “drag” type of wind turbine. The wind pushed the reed sails or “blades” around a central vertical axis pivot point. It was similar to a horizontal axis water paddle wheel turned over on its side. It is called a “panemone” design and can harvest wind flow on only a portion of the windward area it occupies. This concept is used in the three cup anemometers that measure wind speed today. When the velocities of the cups are equal to the wind speed the device has a Tip Speed Ratio (TSR) of 1. This is one of the least efficient designs, though it remains one of the most commonly re-invented wind turbine concepts (commonly referred to as a Savonius VAWT). The Persian VAWT encountered a problem with the windward (or upwind) portion of the rotation cycle, because the rotating sails must travel against the wind. The Persians then built a wall to block the up wind portion of the sails and diverted the wind on to the downwind cycle of the turbine. This was one of the first of many innovative forced deflection techniques that have been used to divert and channel the wind on to a VAWT. Early horizontal axis wind turbines (HAWT) were also invented and became commonly known as “windmills”. Among these were the 4 bladed Dutch and the common multiple bladed farm house type. These windmills where useful in performing tasks such as pumping water or grinding grain and later in producing electricity. Today, wind turbines generally fit into one of two categories; “lift” or “drag” or utilize both forces. In the “drag” devices, the blades are pushed by the wind force (Savonius), while in the “lift” devices the blades are pulled by creating a differential of pressure on their curved surface areas (Darrieus). A VAWT rotates around a vertical axis and is relatively omni-directional. A HAWT rotates around a horizontal axis and must be “pointed” into the wind at all times, and the blades must overcome gravity, generator bearing friction and gear box resistance before the rotation cycle can begin.
(c) Horizontal Axis Wind Turbine (HAWT) Background
The horizontal axis wind turbine HAWT has been used in various forms to perform work or generate electrical energy for many years and has evolved into the 2 and 3 “propeller blade” lift types common today. Certain HAWTs are small scale for house top and sailboat usage while others are very large, and used for utility power generation.
Large HAWT designs are mounted on high towers and must be placed in special areas in order to collect “smooth air flow pressure”. The DOE has shown a recent interest in wind power due to long overdue political pressure to invest in renewable energy techniques and consequently these giant HAWTs have received much of that attention. Some of these turbines are mounted on towers as high as 300 feet and have blades of 100 feet in length. In many cases, permits must be obtained in order to be able to place these towers in the most desirable location. The site must be selected so as to enable the collection of wind flow without any clearance issues or other obstructions. These devices make a loud noise as their blade tips spin through the air at 250 mph or greater (similar to a helicopter rotor blades “whopping” sound). Additional large HAWTs have now been ordered for production around the world. Certain HAWT devices are so large as to make construction, transportation, erection and maintenance a major project. Some of the rotor blades weigh in at more than 10 tons and must be constructed to very close specifications and weights in order to maintain a proper relative balance. Also, the load impact on the horizontal bearing of the large HAWT can be enormous which can often result in maintenance and longevity issues.
Large HAWT designs have certain basic factors in common. The device must be positioned upwind (pointed into the wind). Lift forces on the propeller blades cause the rotation. Some form of brakes and a controller are required. The minimum amount of wind to start the rotation is between 8 and 16 mph. Most can not operate safely above 55 mph or serious damage can occur. These units employ a gear box converter. The main shaft rotor typically rotates at speeds between 30 and 60 rpm; this is then converted into 1000 to 1800 rpm. The generator then produces an A/C voltage on the hi-speed shaft as the output.
Additionally, the wind collection area is so large as to enable simultaneous variable forces to exist that act upon each part of the perspective blades individually and collectively causing unwanted torsional vibrations to occur. This has led to new blade designs in an attempt to control the vortices and perturbations on the rotor blades. New modifications include; devices to detect blade status with transponders using radio signals, magnetic dampening of blade tip vibration schemes, rotor pitch controllers as well as other methods of idling and feathering have been employed. These HAWTs can not re-orient themselves to instant gusts and shifts of wind direction. The device loses its efficiency as it undergoes the enormous stress and flexing forces at work on the blades, this results in distortions and fatigue that invite mechanical failure. The costs of these large HAWTs are enormous and they represent quite an investment for any company or nation. Line loss is also an issue in most installations as towers must be placed away from end use locations.
(d) Vertical Axis Wind Turbine VAWT Background
The problem which the Persian VAWT encountered is still a factor in certain modern VAWT designs. Most VAWT devices share the ability to gather wind force from any azimuth angle, and all VAWT devices share the burden of having to rotate against the wind for a portion of the rotation cycle. This has resulted in a variety of designs and modifications in an attempt to minimize the resistance incurred or to utilize that force during the windward phase of the rotation cycle in order to increase turbine efficiency. Consequently, many improvements have been made to the overall performance of the VAWT in general. New blade designs and stator air channeling devises as well as pivotal blades are among some of these new improvements. One such device, (U.S. Pat. No. 6,688,842 B2, Feb. 10, 2004, Boatner) discloses an example of a pivotal blade turbine mechanism which mechanically adjusts or pivots the blade angles individually, but this device is unable to produce a driving force on a blade in each phase of the rotation cycle.
Additionally, VAWT blade shapes have evolved into a variety of forms. Certain shapes are in the form of the sail of a boat as is incorporated herein by reference (U.S. Pat. No. 7,303,369 B2, Dec. 4, 2007, Rowan and Priest-Brown). This design offers the advantage of creating some lift on the windward phase of the cycle and utilizing the drag force on the downwind cycle. A common problem with certain fixed sail shapes is that they do not trim or adjust themselves with respect to the aspect angle change of the wind's impact upon them. Consequently, there is a portion of the rotation cycle when each of the sails will be at least partially back hauled (or back winded) and will not produce a driving force. At that moment, the turbine will be propelled by the inertia of the apparatus and by the other contributions from the remaining sails in the sequence. Another drawback to certain sail shape designs is that the sails originate near the central axis area in vertical column shapes and are not able to provide a means for the expended air to be sufficiently evacuated, thereby causing a loss in the performance characteristics of the turbine.
Other VAWT designs such as the 2 blade Darrieus type (eggbeater) invented in France (1927), (U.S. Pat. No. 1,835,018 Dec. 8, 1931) have been in use for many years and is referred to here as a “lift” based turbine. The concept experienced some unwanted side effects with harmonic frequencies and difficulties in initiating rotation at low wind speeds. Sandia National Labs has made a great deal of progress with new blade designs and has improved the latter models, however, the concept in general is not new and has lost support and popularity. Also, these VAWTs tend to be very tall devices which must be supported by a large vertical mast and guy wires in order to be kept in an erected position. The unwanted downward thrust and torque loading on the main bearing is tremendous.
Certain other variations of the Darrieus VAWT utilize narrow vertical blades that are mounted at the edge of horizontal struts which emanate from the central vertical axis of rotation. Each of the blades must experience a moment of being broadside (that aspect of being perpendicular) to the oncoming wind and suffer the instantaneous “impulse” force of gusts or shifts in the wind direction acting on the blades. This “impulse” force often tends to produce a shudder or vibration in such devices. This shuddering produces unwanted instabilities and distortion of the blade alignment which alters the momentum of the turbine in a degenerative manner. Early models such as the “Giromill” and “Cycloturbine” experienced undesirable pulsatory torque, flexing and bending moments. Later designs improved the torque problem by using helical twists on the blades. However, in high winds the wing tip velocities and centrifugal forces acting upon the narrow vertical blades tends to distort the individual alignment and calibration of the blades. Therefore, the perspective skew, orthogonality, pitch, and droop are altered individually and this creates a variance of the pathways through the air for each blade. This effect makes each blade imperfect in its own peculiar fashion; each blade then creating its own non-synchronous eddies and unique burbles relative to each other. This distortion causes unpredictable turbulence for the successive blades in the rotation sequence, resulting in an overall decrease in the efficiency as well as increasing the noise of the turbine. Certain designs attach the top and bottom blade tips into a circular band in an attempt to minimize the distortion of the individual blade alignment. Still other designs employ two or more sets of horizontal strut assemblies in order to maintain the blades in proper alignment. While these modifications improve the anomalous distortion of the blade alignments described previously, they also require additional parts and added weight. These parts also damage the wind flow through the device, which is the basis for its cross wind lift concept. One such example is referred herein and is disclosed in (U.S. Pat. No. 5,451,137 Sep. 19, 1995, Gorlov). While the Gorlov VAWT has reduced the pulsatory torque problem of prior Giromills, and has made start up easier, it must attain high speeds to provide any significant amount of power output which requires a rather windy location. This design still depends on cross wind lift, which is disturbed on the leeward side of the cycle by irregular flow currents due to Von Karman street vortices created by the windward passage of the diagonal helical blades. This turbulence varies as a function of the rotation speed of the blades as well as the wind velocity producing a variety of harmonic instabilities at certain rotor and wind speed combinations that are chaotic and periodically unpredictable.
The Savonius VAWT is a “drag” based device generally having a TSR of one and is disclosed herein (U.S. Pat. No. 1,697,574, Jan. 1, 1929, Savonius). The device can be described as halving two opposing cylinder halves attached lengthwise and vertically on to a vertically rotating shaft with the interior and exterior sides connected to the shaft so as to produce an “S” shape. Consequently, one cylinder half aperture is open and exposed to the wind as the other half is closed and they then alternate as the device rotates. This concept will only produce a limited amount of power through a full cycle of rotation. Many derivatives of this concept have evolved including a certain design using a helical shaped blade that induces a vortex effect, which is incorporated herein by reference (U.S. Pat. No. 7,494,315 Feb. 24, 2009, Hart). However, the device tends to be substantially vertical, and the height to width ratio could become somewhat excessive which may also lend itself to increased torque loading impact on the vertical shaft bearing (in larger models). In addition, the device's ability to develop substantial torque through the inertial forces available on a rotating platform are hampered by the small radius of the base itself, and in certain models may require a flywheel type of contraption for added stability.
Certain other VAWT designs utilize a booster or stator channeling device in order to divert air flow on to the “drag” or downwind portion of the rotor blades. These stator boosters or external channeling devices effectively block or redirect the wind from encountering the rotor blades on the windward or upwind cycle while diverting the wind primarily on to the downwind cycle. While this does increase the performance of the rotor, it is also at the cost of eliminating or reducing most of the “lift” characteristics of the device. Consequently, these deflector stator devices create the presence of blind spots or screening angles that can distort the air flow over the rotor blades which then reduces the possible efficiency of the device in any specific wind field collection area. Incorporated herein as reference are prior art devices of this type (U.S. Pat. No. 6,465,899 B2, Oct. 15, 2002 Roberts), (U.S. Pat. No. 5,852,331 Dec. 22, 1998 Giorgini), (U.S. Pat. No. 7,573,148 B2 Aug. 11, 2009 Nica).
(E) Golden Ratio Vertical Axis Wind Turbine (GRVAWT) Background
Developing a new apparatus often requires re-examination of basic truths in order to consider a concept without preclusion, preconception and prejudice to prior art. Traditionally, science has been used to study nature in order to achieve many fundamental objectives. Harnessing wind force by utilizing the concept of the Golden Ratio along with examining the natural and physical science that reveals itself in the footprints of creation has resulted in the concept of the present invention Golden Ratio VAWT (GRVAWT). These golden ratio foot prints are Universal and it is outside of the scope or purpose of this document to list them. However, it is relevant to note that these foot prints exist in galaxy spirals, hurricane spirals, sea shells, plants, animals, and in the human body. In reality, they are a fundamental part of the very building blocks of creation. The Creator has chosen these circular, spherical, spiracle and elliptical shapes in the natural, physical and astronomical world around us purposely. These forms vary in size from celestial bodies to atoms and these shapes and ratios are commonly revealed in these golden ratio foots prints. The present invention incorporates these shapes in a harmonious natural blend of golden ratios that produces an unprecedented and perfect adaptation of a natural wind engine which is in balance with the wind itself by its own nature. The golden ratio or golden section is often represented by the Greek letter Phi. Phidias (Phi) and Plato officially acknowledged the golden ratio and termed it the “Divine Proportion” as early as 400 BCE. It was then articulated mathematically by Euclid of Alexandria around 300 BCE and was described in chapter 5 of his books “Elements”. The golden ratio is approximately=1.618; and in a line segment where a=1 and b=0.618, then a +b=1.618. In mathematics two quantities are found in the Golden Ratio if the ratio between them is 1 to 0.618 and 1.618 to 1. This can be expressed algebraically as: a+b divided by a=a divided by b=Phi, which also equates to a+b is to a, as a is to b, or mathematically as (1 plus the square root of 5 divided by 2)=1.618 or Phi.
  formula  =                                          (            PHI            )                                                φ                      =                            1          +                      5                          2            =      1.618      
Examine the formation of a tropical cyclone from a satellite view, having its golden ratio spiral bands emanating from its central eye. This is not a random occurrence, but rather one that repeats itself storm after storm on Earth and on other planets in our solar system. The anatomical features of cyclones are not accidental, they are part of a natural selection process caused by the rotation of earth and its interaction with the atmosphere and oceans. This design is then a “principle of least effort” and maximum efficiency. These cyclones are “nature's choice” for a wind engine. Learning from these observations, has resulted in designing a wind turbine that functions with these same principles and is therefore naturally efficient. By utilizing these golden ratios and shapes, the present invention incorporates this “Regenerative” force that is not available in prior art.
Also, consider that a large bolder in a river current has more force being exerted upon it than a narrow reed. Therefore, the larger the surface area of an object, the more force is able to be exerted upon it, and consequently, greater is the potential to extract power from that object. The boulder has displaced more space in the river current than the reed. The potential speed and torque force of an object as relates to the present invention is also a result of the greater amount of lift force available on the larger wings. This is due to the GRVAWT large surface area wings ability to displace more wind space than the narrow blades of Betz's theory, which enables the present invention to develop more power from the same air space as compared to prior art. Study a knot in a piece of wood and examine the growth ring lines that are being constricted together as they pass around the knot and then follow these lines until they regain normal spacing again (the knot has displaced the space in the tree). This is also apparent when recalling Albert Einstein's theory of relativity wherein he discovered that an object in space (or anywhere) displaces that portion of space and the space itself becomes constricted around that object. Furthermore, the amount of energy available in an object is directly proportional to its mass (E=mc2). Therefore, the greater the size of an object the more space it displaces even if it has a low mass density. Consequently, it is an object of the present invention to utilize its unique golden ellipse vertical profile to displace the wind space. The wind currents can not effectively pass through the apparatus (in rotation) and must compress and accelerate as they pass around the ellipse profile of the rotating turbine. This causes the pressure gradient on the convex wing surface to tighten. This phenomena can be seen in the compression or tightening of isobars between high and low pressure systems when they interact (the tightly spaced isobars depict high wind velocity). Therefore, the greater the surface area of the golden ratio wings, the larger the golden ratio ellipse, which causes a tighter pressure gradient and more wind force is made available to the turbine collection area than in prior art VAWTs or HAWTs.
(d) Need for Present Invention
The present invention has been realized in order to provide a new bio-mechanical GRVAWT concept which provides solutions to prior art VAWT shortcomings (Darrieus and its derivatives and Savoniuos and its derivatives) and to obtain remarkable efficiency without HAWT shortcomings as well as being very quiet and extremely appealing. The GRVAWT is simple and scalable in size or number of wings and easily accommodates any requirement in an urban or commercial environment. Additional embodiments and configurations include usages as in a pump apparatus providing gas or liquid flow output when the rotor is driven by a motor.
It is desirable to have a turbine generator that can make use of any wind from virtually any direction (Vertical or Horizontal) and in any axis, simultaneously. A GRVAWT that is light weight, affordable, reliable and that can produce useful energy at low wind speeds and continue to operate in very high wind speeds without harming itself and with a low loading impact on its base support structure. A new GRVAWT energy conservation apparatus that produces full conservation of angular momentum resulting in economy.
It is also desirable to have a turbine that does not require any additional exotic external airflow deflection techniques or pivotal contraptions such as those used in prior VAWT designs, but rather utilizes the upwind phase of the rotation cycle to produce a driving regenerative force. Again, it is desirable to have a turbine system that can be fixed or mobile, which can be positioned on land or at sea and that is also ideal for roof top and masthead installations. The present invention can also be configured as a mobile unit for DOT to power temporary road signs or as a portable military and emergency turbine that is combined with a diesel generator set and used to provide support in remote or storm stricken locations. As a result of the scalable design, the present invention is a versatile device which can be used as a utility grid source or in smaller applications such as: camping, picnicking, boating, traveling, providing battery charging for fans, lights, audio-video devices, toys, computers and digital devices (as a “Fun” source of portable energy).